In my application last year in Sydney I provided a bank statement showing 6 months of transactions and a utility bill and strata levy bill to prove address, I had no issues with the application
I think the visa is a success as the DTV crowd are staying for long periods. I’d normally spend one month a year in Thailand, in 2025 with the DTV I’ll spend about 6 months here, I live it up a bit and will easily spend over a million baht here, way more than I would in a normal year.
I drafted my own letter for my employer to sign based on terms we had mutually agreed, I don’t see any issue with doing this if it greatly speeds up getting it signed.